为所有类执行此操作

目标C：

NSArray *secItemClasses = @[(__bridge id)kSecClassGenericPassword,
                       (__bridge id)kSecClassInternetPassword,
                       (__bridge id)kSecClassCertificate,
                       (__bridge id)kSecClassKey,
                       (__bridge id)kSecClassIdentity];
for (id secItemClass in secItemClasses) {
    NSDictionary *spec = @{(__bridge id)kSecClass: secItemClass};
    SecItemDelete((__bridge CFDictionaryRef)spec);
}

斯威夫特：

let secItemClasses = [kSecClassGenericPassword, kSecClassInternetPassword, kSecClassCertificate, kSecClassKey, kSecClassIdentity]
for itemClass in secItemClasses {
    let spec: NSDictionary = [kSecClass: itemClass]
    SecItemDelete(spec)
}

Xamarin iOS版本（MonoTouch）的accepted answer上 * 如何删除所有钥匙串项目可访问的应用程序 * 如下：

foreach (var recordKind in new []{
                SecKind.GenericPassword,
                SecKind.Certificate,
                SecKind.Identity,
                SecKind.InternetPassword,
                SecKind.Key,
            })
    {
          SecRecord query = new SecRecord(recordKind);
          SecKeyChain.Remove(query);
    }

如果您想确保确实删除了记录，您可以在开发过程中使用以下代码检查特定类型的KeyChain中前后的项目数：

SecStatusCode scc;
var records = SecKeyChain.QueryAsRecord(new SecRecord(SecKind.GenericPassword), 1000, out scc);

我在《斯威夫特》中改写了戴杰-詹的回答：

let secItemClasses = [kSecClassGenericPassword,
    kSecClassInternetPassword,
    kSecClassCertificate,
    kSecClassKey,
    kSecClassIdentity]
for secItemClass in secItemClasses {
    let dictionary = [kSecClass as String:secItemClass]
    SecItemDelete(dictionary as CFDictionary)
}

快速版本

import Foundation
import Security

public class Keychain: NSObject {
  public class func logout()  {
    let secItemClasses =  [
      kSecClassGenericPassword,
      kSecClassInternetPassword,
      kSecClassCertificate,
      kSecClassKey,
      kSecClassIdentity,
    ]
    for itemClass in secItemClasses {
      let spec: NSDictionary = [kSecClass: itemClass]
      SecItemDelete(spec)
    }
  }
}

用法：

Keychain.logout()

感谢Daij-Djan，我得到了这个解决方案：

for (id secclass in @[
     (__bridge id)kSecClassGenericPassword,
     (__bridge id)kSecClassInternetPassword,
     (__bridge id)kSecClassCertificate,
     (__bridge id)kSecClassKey,
     (__bridge id)kSecClassIdentity]) {
    NSMutableDictionary *query = [NSMutableDictionary dictionaryWithObjectsAndKeys:
                                  secclass, (__bridge id)kSecClass,
                                  nil];

    SecItemDelete((__bridge CFDictionaryRef)query);        
}

不幸的是，这个问题的所有答案似乎都过时了（自iOS 7.0+以来），因为它们不会删除设置了kSecAttrSynchronizable标志的钥匙串条目（允许通过iCloud同步到其他设备）。
要删除这样的条目，crucible需要向删除查询添加一个条目，指定kSecAttrSynchronizable: kSecAttrSynchronizableAny：

快速版本：

let secItemClasses = [kSecClassGenericPassword,
    kSecClassInternetPassword,
    kSecClassCertificate,
    kSecClassKey,
    kSecClassIdentity]
for secItemClass in secItemClasses {
    let query: NSDictionary = [
        kSecClass as String: secItemClass,
        kSecAttrSynchronizable as String: kSecAttrSynchronizableAny
    ]
    SecItemDelete(query)
}

你可以看看实用程序文件夹中的钥匙链访问应用程序。如果你启动应用程序并点击“所有项目”，它应该会显示你用这台特定计算机创建的所有项目。开发人员的通常以com开头。

当你使用Mac作为目标进行单元测试时，使用kSecClassCertificate清除所有证书时要小心，因为这会清除你的开发证书。你可以简单地撤销现有的证书，但在CI/CD管道中这是行不通的。